One in five movies to hit cinemas this year will be sequels – a record figure – according to a new report.

Website Box Office Mojo says there will be 27 movies which are either followups, prequels or spin-offs from former properties in 2011, up from a previous high of 24 in 2003. By contrast, last year was a relative oasis of originality with just 19 "sequels" hitting the big screen.

High-profile followups due to arrive this year include Transformers 3: Dark of the Moon, Pixar's Cars 2, X Men: First Class and the final Harry Potter episode, the Deathly Hallows (part two). Lesser known sequels include Piranha 3DD, which presumably is promising even more flesh than the previous eye-popping instalment, Diary of a Wimpy Kid 2 and Big Mommas: Like Father, Like Son, with Martin Lawrence reprising his role as the titular corpulent matriarch.

Nine of the 27 sequels will be second movies, while five will be third films, or "threequels" as they have been dubbed. A record five films, including Mission: Impossible Ghost Protocol and Pirates of the Caribbean: On Stranger Tides will be fourth instalments and an unprecedented five will reach their fifth entry (Fast Five, Final Destination 5, Puss in Boots, X-Men: First Class, Winnie the Pooh). Two franchises, The Muppets and Planet of the Apes, will reach their seventh effort, and one (Harry Potter) will make it all the way to eight.

Box Office Mojo's Brandon Gray told the Daily Telegraph: "Hollywood is dipping into the well of past glory more than ever. It's truly unfortunate that the story is held in such little regard."

In the report Box Office Mojo predicted that Harry Potter would be the highest-grossing film of the year, carrying the series past Star Wars in terms of overall box office gross, though not audience numbers.